Technologies such as microelectronics, micromechanics and biotechnology have created a high demand for structuring and probing specimens within the nanometer scale. Micrometer and nanometer scale process control, inspection or structuring, is often done with charged particle beams. Probing or structuring is often performed with charged particle beams which are generated and focused in charged particle beam devices. Examples of charged particle beam devices are electron microscopes, electron beam pattern generators, ion microscopes as well as ion beam pattern generators.
For inspecting a sample with a charged particle beam device, the particle beam is directed on a sample. By the impingement of the primary particle beam on the sample, a secondary beam of signal particles is generated. For example, charged signal particles are secondary charged particles which are backscattered from, transmitted through, and/or scattered by the specimen. Moreover, secondary charged particles, which are generated upon interaction of the primary charged particles with the specimen, are also referred to as charged signal particles.
The throughput of the samples is an important factor with regard to the efficiency of a charged particle beam device. As the inspection may be part of the production process, a fast inspection process is desirable. Apart from sample change, beam calibration and beam scanning, one of the limiting factors is the response time of the detector.
Furthermore, particle beam devices are known, which provide a more precise signal generation by improving the separation of the primary and the secondary particle beam or by separating different secondary particle beams in case a plurality of primary particle beams are used in order to speed up the inspection process.